1. Field of the Disclosure
The disclosure generally relates to manufacturing lined tubing. In particular, the disclosure relates to a method of manufacturing copper lined coiled tubing.
2. Background Art
Casing joints, liners, and other oilfield country tubular goods (“OCTGs”) are frequently used to drill, complete, and produce wells. For example, casing joints may be placed in a wellbore to stabilize and protect a formation against high wellbore pressures (e.g., wellbore pressures that exceed a formation pressure) that could otherwise damage the formation.
Steel pipe may be manufactured in various configurations, one of which is seamless, another which is seamed or welded pipe. Seamless pipes are typically more light weight and have thinner walls, while welded pipes are heavier and more rigid. Welded pipe may also have a better consistency and are typically straighter. Further, welded pipe may typically be used in instances when the pipe is not put under a high degree of stress.
Certain pipe characteristics may be controlled during production. For example, the diameter or wall thickness of the pipe may often be modified depending on how the pipe may be used. Often the type of steel will also have an impact on pipe's the strength and flexibility. Other controllable characteristics include length, coating material, and end finish.
Welded steel pipe is commonly made from heavy strip or plates of hot-rolled steel, called skelp, provided in long pieces or coiled lengths, which have their longitudinal edges finished appropriately for butt welding together when the skelp is brought into a cylindrical configuration. Such shaping of the skelp into tubular form may be achieved by suitable roll means, such as successive concave rollers through which the skelp is advanced while the rollers progressively bend it about a longitudinal axis intended for the finished tube. In the case of very large diameter pipe (e.g. about 25 inches or more in diameter), a stand of long, heavy rolls on axes parallel to the desired pipe axis, which bend an entire length of partly bent, sidewise-received skelp into the intended shape may be used.
In these or other ways, the skelp is brought, progressively or as a complete piece, into a cylindrical form, with a narrow, longitudinal cleft between the edges of the skelp. Then further rolls or other means compress the outside of the pipe blank to close the cleft, as it passes or is passed by a welding means, which welds the butted edges together. For large diameter pipe, such electrical welding may be of the submerged arc type, on the outside of the cleft, with a second, subsequent weld by another consumable electrode along the inside.
Referring to FIG. 1, an apparatus and process to manufacture welded pipe 100 is shown. Before being manufactured, material used for welded pipe may be stored in a sheet configuration (i.e., skelp) and wound up on a roll (not shown). Initially, the skelp is unrolled and fed to rollers 102. The skelp is then passed through a series of grooved rollers, which cause the edges of the sheet to begin to “curl” together 104, finally forming an unwelded pipe. The unwelded pipe next passes by an induction welding apparatus and a high pressure roller 106, both of which seal the edges of the pipe together and form a tight weld. Finally, the pipe may be cut to a desired length and stacked for further processing 108, or remain uncut and coiled to form coiled tubing.
U.S. Pat. No. 7,012,217 (“Titze”) discloses a method and apparatus for making large diameter welded pipes. A leading end of a hot strip may be connected to a trailing end of a leader strip and then subjected to a two-stage leveling for strip flatness in transverse direction and strip flatness in longitudinal direction. The entire surface of the hot strip including strip edges thereof may be inspected by ultrasound and the strip edges are prepared in four stages before being pre-bent. The hot strip may be then shaped into a slotted tube and the strip edges are welded along the inner and outer sides by laser to produce the pipe. Further, U.S. Pat. No. 4,410,369 (“Waid”) discloses a method of rolling a sheet to a pipe shape, the edge zones of which are then electrically butt welded together.
Introducing a second liner layer to be rolled may present a new degree of difficulty in manufacturing welded pipe. What is needed therefore, is a method to manufacture a lined pipe in which a width of the lining material may be calculated. Such a method may help remove trial and error from the process and would be well received in industry.